1. Field of the Invention
The invention relates generally to mechanisms employed to raise and lower groupings of luminaires or other apparatus mounted to a support assembly and positionable at or near a distal end of a mast such as a high mast as is useful for illumination of a roadway or the like, the invention particularly relating to a latching mechanism of compact conformation permitting configuration of a relatively low profile support assembly having improved operation and esthetic appeal.
2. Description of the Prior Art
Clusters of luminaires intended for outdoor illumination have long been mounted to a support ring capable of being hoisted to or near the top of a “high mast”, typically through use of a winch and associated hoisting cables, the support ring being readily lowered for necessary maintenance, repair or replacement of the luminaires. In certain applications, devices other than luminaires are mountable by a support ring for raising/lowering of the resulting assembly along a high mast, reference herein to luminaires so mounted encompassing such other devices. In accomplishment of the functions so noted, the support ring carrying the luminaires must be mounted for movement along the mast between a lowermost or ground-level position necessary for servicing and the like and an operational uppermost position at or near the top of the mast at which the luminaire-bearing support ring is releasably yet positively latched to a stationary support permanently located at an upper portion of the mast. Latching mechanisms typically employed for accomplishing such functions include a latch pin carried by the support ring, such latch pins engaging latch barrels mounted to the stationary support permanently mounted at the top of the mast. Mating of a number of the latch pins with a corresponding number of the latch barrels on completion of the hoisting operation results in positive engagement between the latch pins and the latch barrels sufficient to latch the support ring to the stationary support until disengagement to allow the luminaire-bearing support ring to be lowered back to the ground as desired. Latch barrels such as are common in the prior art are mounted substantially vertically with openings disposed downwardly to permit receipt of one each of the latch pins into said opening as the latch pins engage the latch barrels, the latch pins being necessarily oriented in a vertical sense in order to provide the desired function. Vertical orientation of the latch pins and latch barrels unavoidably cause the assembly resulting from the mating of the support ring and stationary support to be less than compact in “height”, thereby lending a bulky appearance to the resulting assembly. Prior high mast lighting systems, while functional mechanically and useful for accomplishment of intended operation, have not generally exhibited esthetic appeal due at least in part to an unavoidable height dimension relative to other dimensions of known support ring/stationary support assemblies. Further, mechanical sub-assemblies of prior art systems are typically exposed to view and are therefore lacking in esthetic appeal. An architecturally appealing high mast hoisting system could be realized by the ability to reduce the height of such assemblies along with the ability to cleanly mate the support ring with the stationary support so that the assembly appears as an essentially unitary enclosure or housing from which luminaire-mounting arms cleanly and attractively extend for mounting of luminaires or the like. Attainment of an architecturally appealing structure at reduced cost lends increased improvement over the prior art, such cost reduction being realized in part by elimination of costly and bulky latch barrels. Such bulky latch barrels, when exposed to view, are lacking in esthetic appeal. Prior art difficulties associated with jamming of latch pins with camming surfaces disposed within the interior of latch barrels would preferably be avoided by improved latch pin structure having cam-following pins positively engageable with such camming surfaces without the tendency to “cock” or tilt with resultant jamming.
The prior art is replete with systems proposed for use and which are actually used for raising and lowering luminaire assemblies along high mast poles, such prior systems being deficient in esthetic appeal as alluded to hereinabove. Typical prior art systems include that system described by Murray et al in U.S. Pat. No. 4,234,165, in which a circular support ring carrying luminaires is hoisted along a high mast pole to an operational position adjacent a cylindrical housing disposed atop the pole, the housing covering a stationary support. The support ring simply abuts the housing and is not esthetically pleasing in appearance. Luminaires carried by a support ring are raised and lowered according to the teachings of Garchinsky in U.S. Pat. No. 4,228,488, the support ring abutting a housing covering a stationary support mounted atop a high mast pole on completion of the raising function, the result being less than esthetically pleasing. Latimer, in U.S. Pat. No. 5,975,726 discloses a high mast lighting system comprised of a luminaire-bearing annular support ring which fails to visually integrate with a covering housing fixed atop a high mast pole on hoisting of the support ring to an operational position adjacent the housing. Blahut, in U.S. Pat. No. 4,115,845, fails to provide a high mast system with visual appeal. Garchinsky, in U.S. Pat. Nos. 4,149,230 and 4,429,355 discloses high mast assemblies of conventional appearance. The appearance of the high mast systems disclosed by Richter in U.S. Pat. No. 6,261,122 and Thompson in U.S. Pat. No. 4,139,884 is essentially less than pleasing as are the systems disclosed by Staniec in U.S. Pat. No. 6,074,075; Hunt et al in U.S. Pat. No. 3,633,980; Savoca in U.S. Pat. No. 5,718,602; Richter in U.S. Pat. No. 6,261,122 and Thompson in U.S. Pat. No. 4,348,717 inter alia.
The art has experienced a long-felt need for a high mast hoisting system having architectural esthetics as well as a favorable cost profile. The present high mast system addresses such needs by providing a luminaire-bearing support ring of a shape and dimensions permitted in part by a low profile latching mechanism that further permits economies of cost in the construction of a system used in environments within which the invention is intended.